U.S. patent application number 12/430471 was filed with the patent office on 2009-08-20 for method, apparatus and system for transmitting ethernet signals in optical transport network.
Invention is credited to Ming CHEN, Qiuyou WU.
Application Number | 20090208208 12/430471 |
Document ID | / |
Family ID | 39689641 |
Filed Date | 2009-08-20 |
United States Patent
Application |
20090208208 |
Kind Code |
A1 |
CHEN; Ming ; et al. |
August 20, 2009 |
METHOD, APPARATUS AND SYSTEM FOR TRANSMITTING ETHERNET SIGNALS IN
OPTICAL TRANSPORT NETWORK
Abstract
A method, apparatus and system for transmitting Ethernet signals
in an OTN are provided. The method may include: mapping the
Ethernet signals to timeslot units, where a VCG composed of
multiple OPUs is divided into the timeslot units; mapping the
Ethernet signals into the OPUs, and then mapped into OTUs and
output to the OTN for transmitting. In this way, the Ethernet
signals may be transmitted in the OTN transparently. The apparatus
may further include: a first adaptation protocol frame mapping
module, a first virtual concatenation module, and a first line
terminal module, which convert the Ethernet signals to the OTUs.
The system may include a first adaptation protocol frame mapping
module, a second adaptation protocol frame mapping module, a first
virtual concatenation module, a second virtual concatenation
module, a first line terminal module, and a second line terminal
module, which convert the Ethernet signals to the OTUs and vice
versa.
Inventors: |
CHEN; Ming; (Shenzhen,
CN) ; WU; Qiuyou; (Shenzhen, CN) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
39689641 |
Appl. No.: |
12/430471 |
Filed: |
April 27, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/CN2008/000189 |
Jan 25, 2008 |
|
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|
12430471 |
|
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Current U.S.
Class: |
398/45 |
Current CPC
Class: |
H04J 14/0273 20130101;
H04J 14/0227 20130101; H04J 3/1658 20130101; H04J 14/02 20130101;
H04J 2203/0085 20130101 |
Class at
Publication: |
398/45 |
International
Class: |
H04J 14/00 20060101
H04J014/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 9, 2007 |
CN |
200710063783.8 |
Claims
1. A method for transmitting Ethernet signals in an Optical
Transport Network, OTN, comprising: mapping the Ethernet signals
into adaptation protocol frames; dividing a Virtual Concatenation
Group, VCG, composed of multiple Optical channel Payload Units,
OPUs, into multiple timeslot units; mapping the adaptation protocol
frames to the timeslot units; and mapping mapped OPUs into Optical
channel Transmission Units, OTUs, and outputting the OTUs to the
OTN for transmitting.
2. The method according to claim 1, wherein mapping the Ethernet
signals into the adaptation protocol frames comprises: mapping the
Ethernet signals into the adaptation protocol frames through
Generic Framing Procedure-Transparent, GFP-T, encapsulation or
Generic Framing Procedure-Framing, GFP-F, encapsulation.
3. The method according to claim 2, further comprising: inserting
an idle frame or adaptation protocol management frame into the
adaptation protocol frames after the Ethernet signals are mapped
into the adaptation protocol frames.
4. The method according to claim 1, wherein mapping the Ethernet
signals into the adaptation protocol frames further comprises:
adding a connection sequence check byte into a reserved overhead
byte of the adaptation protocol frames.
5. The method according to any one of claim 1, wherein dividing the
VCG into the multiple timeslot units comprises: dividing the VCG
into the multiple timeslot units adaptable to the Ethernet signals
according to a rate of the Ethernet signals.
6. The method according to claim 5, wherein: the Ethernet signals
are two channels of 100GE signals; the VCG is composed of five OPUs
whose rate level is 3; and the multiple timeslot units are two
timeslot units.
7. The method according to any one of claim 1, wherein before the
Ethernet frames are mapped into the adaptation protocol frames, the
method further comprises: adjusting a quantity of the OPUs in the
VCG dynamically through a Link Capacity Adjustment Scheme, LCAS,
according to preset parameters or current link traffic.
8. The method according to claim 1, further comprising: receiving
the OTUs sent from the OTN, and demapping the OTUs into the OPUs;
assembling the OPUs into the VCG, and demapping the VCG into the
adaptation protocol frames; and demapping the adaptation protocol
frames into the Ethernet signals.
9. An apparatus for transmitting Ethernet signals in an Optical
Transport Network, OTN, comprising: a first adaptation protocol
frame mapping module, adapted to map Ethernet signals to adaptation
protocol frames; a first virtual concatenation module, adapted to
divide a Virtual Concatenation Group, VCG, composed of multiple
Optical channel Payload Units, OPUs, into timeslot units, and map
the adaptation protocol frames to the timeslot units; and a first
line terminal module, adapted to map the OPUs into Optical channel
Transmission Units, OTUs, and output the OTUs to the OTN.
10. The apparatus according to claim 9, wherein: the apparatus
further comprises a management and control module, adapted to
generate a capacity control command; and the first virtual
concatenation module adapted to adjust the capacity of a link
between the first virtual concatenation module and the first line
terminal module according to the capacity control command.
11. The apparatus according to claim 10, wherein: the first
adaptation protocol frame mapping module is further adapted to
detect traffic of the Ethernet signals; and the management and
control module adapted to generate the capacity control command for
adjusting the capacity of the link according to the traffic of the
Ethernet signals detected by the first adaptation protocol frame
mapping module.
12. An apparatus for recovering Ethernet signals from Optical
channel Transmission Units, OTUs, comprising: a second line
terminal module, adapted to demap the OTUs received from an Optical
Transport Network, OTN, into Optical channel Payload Units, OPUs; a
second virtual concatenation module, adapted to assemble the OPUs
in response to demapping performed by the second line terminal
module into a Virtual Concatenation Group, VCG, and demap the VCG
into adaptation protocol frames; and a second adaptation protocol
frame mapping module, adapted to demap the adaptation protocol
frames that derive from demapping performed by the second virtual
concatenation module into Ethernet signals, and output the Ethernet
signals to an Ethernet.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of international
application number PCT/CN2008/000189, filed on Jan. 25, 2008, which
claims priority to the Chinese Patent Application No.
200710063783.8, filed with the Chinese Patent Office on Feb. 9,
2007, and entitled "A method, Apparatus and System for realizing
transmitting Ethernet signal in the optical transport network,"
both of which are incorporated herein by reference in their
entirety.
TECHNICAL FIELD
[0002] The present invention relates to Optical Transport Network
(OTN) transmission technology and, in particular, to a method,
apparatus, and system for transmitting Ethernet signals in an
OTN.
BACKGROUND
[0003] Synchronous Digital Hierarchy (SDH) is based on time
division multiplexing technology, and provides a time division
multiplexing transmission channel of a fixed bandwidth. However,
with the rapid development of data communication and in view of the
burst feature and unpredictability of data services, currently
applied SDH technology is less and less adaptable to explosively
growing data services.
[0004] In order to meet the requirements of explosively growing
data services, the International Telecommunications
Union-Telecommunications (ITU-T) integrated some features of SDH
technology with the bandwidth extension technology of the Dense
Wavelength Division Multiplexing (DWDM) to formulate the OTN
standard series. The OTN technology includes electrical-layer and
optical-layer technical specifications, and provides a Tandem
Connection Monitoring (TCM) processing method and a Forward Error
Correction (FEC) method to schedule and manage high-capacity
services flexibly.
[0005] Currently, in order to transmit high-capacity data, more and
more services use an OTN to transmit data. For example, 100 G
Ethernet, representative of the mainstream Metropolitan Area
Network (MAN) technologies, adapts to the signals transmitted on
the OTN in the following two methods.
[0006] The first method adapts the 100GE signals for a Virtual
Concatenation Group (VCG) composed of 11 Optical channel Payload
Units (OPUs) whose rate level is 2 (namely, the rate is 10 Gbps)
(OPU2-11v). More specifically, the adaptation may include, decoding
the 100GE signals, encapsulating the decoded signals through a
General Framing Procedure (GFP), mapping the encapsulated signals
to 11 OPU2 virtual concatenation units, and sending the signals to
the OTN for transmitting.
[0007] The second method adapts the 100GE signals for a VCG
composed of three OPUs whose rate level is 3 (namely, the rate is
40 Gbps) (OPU3-3v). Using the second method, the adaptation may
include, decoding the 100GE signals, encapsulating the decoded
signals through a GFP, mapping the encapsulated signals to three
OPU3 virtual concatenation units, and sending the signals to the
OTN for transmitting.
[0008] The aforementioned methods, however, have defects. For
example, in the method which adapts the 100GE signals for the
OPU2-11v, the signals of a 100 G bandwidth are adapted for an
11*2.5 G bandwidth, thus wasting a bandwidth of about 9.95 G.
Moreover; the transmission cost is high because 11 chromatic
wavelengths are occupied. Further, in the method which adapts the
100GE signals for the OPU3-3v, the signals of a 100 G bandwidth are
adapted for a 3*40 G bandwidth, thus causing enormous bandwidth
waste of about 20.45 G and reducing the transmission
efficiency.
SUMMARY
[0009] A method, apparatus and system for transmitting Ethernet
signals in an OTN are disclosed in various embodiments of the
present disclosure to improve the bandwidth utilization ratio and
reduce the transmission cost.
[0010] A method for transmitting Ethernet signals in an OTN
consistent with some embodiments may include: mapping an Ethernet
signal to an adaptation protocol frame; dividing a VCG composed of
multiple OPUs into multiple timeslot units; mapping the adaptation
protocol frame to the timeslot units; and mapping the mapped OPUs
into Optical channel Transmission Units (OTUs), and outputting the
OTUs to the OTN for transmitting.
[0011] In the foregoing solution, a VCG composed of multiple OPUs
is divided into multiple timeslot units adaptable to Ethernet
signals so that Ethernet signals are mapped to the OPUs, and then
mapped to the OTUs and output to the OTN. Therefore, the Ethernet
signals may be transmitted in the OTN transparently, the bandwidth
utilization ratio may be improved greatly, the wavelength
utilization may be optimized, and the cost of transmitting Ethernet
signals in the OTN may be reduced.
[0012] An apparatus for transmitting Ethernet signals in an OTN
consistent with some embodiments may include: a first adaptation
protocol frame mapping module, adapted to map an Ethernet signal
into an adaptation protocol frame; a first virtual concatenation
module, adapted to divide a VCG composed of multiple OPUs into
timeslot units, and map the adaptation protocol frame to the
timeslot units; and a first line terminal module, adapted to map
the OPU into an OTU, and output the OTU to the OTN.
[0013] The first adaptation protocol frame mapping module in the
foregoing apparatus solution performs adaptation protocol
encapsulation for an Ethernet signal, the first virtual
concatenation module maps the adaptation protocol frame into the
VCG, and the first line terminal module maps the OPU into the OTU
and transmits the OTU to the OTN, thus converting an Ethernet
signal into an OTU. Afterward, the OTU is sent to the OTN, thus
implementing transmission of an Ethernet signal in the OTN.
[0014] An apparatus for recovering an Ethernet signal from an OTU
consistent with some embodiments may include: a second line
terminal module, adapted to demap the OTU sent by the OTN into an
OPU; a second virtual concatenation module, adapted to: assemble
the OPUs that derive from demapping performed by the second line
terminal module into a VCG, and demap the VCG into an adaptation
protocol frame; and a second adaptation protocol frame mapping
module, adapted to demap the adaptation protocol frame that derives
from demapping performed by the second virtual concatenation module
into an Ethernet signal, and output the signal to the Ethernet.
[0015] In the foregoing apparatus for recovering an Ethernet signal
from the OTU, the second line terminal module demaps the OTU into
an OPU, the second virtual concatenation module demaps the OPU into
an adaptation protocol frame, and the second adaptation protocol
frame mapping module converts the adaptation protocol frame into an
Ethernet signal, and sends the signal to the Ethernet. In this way,
the Ethernet signal is recovered from the OTU that bears the
Ethernet signal, and sent to the Ethernet for further
transmission.
[0016] A system for transmitting Ethernet signals in an OTN
consistent with some embodiments may include: a first adaptation
protocol frame mapping module, adapted to map an Ethernet signal
into an adaptation protocol frame; a first virtual concatenation
module, adapted to divide a VCG composed of multiple OPUs into
timeslot units, and map the adaptation protocol frame to the
timeslot units; a first line terminal module, adapted to map the
OPU to an OTU, and output the OTU to the OTN; a second line
terminal module, adapted to demap the OTU received from the OTN
into an OPU, where the OTU is output by the first line terminal
module to the OTN; a second virtual concatenation module, adapted
to assemble the OPUs that derive from demapping performed by the
second line terminal module into a VCG, and demap the VCG into an
adaptation protocol frame; and a second adaptation protocol frame
mapping module, adapted to demap the adaptation protocol frame that
derives from demapping performed by the second virtual
concatenation module into an Ethernet signal, and output the signal
to the Ethernet.
[0017] Through the foregoing system for transmitting Ethernet
signals in the OTN, an Ethernet signal may be sent to the OTN for
transmission, and the Ethernet receives the OTU that bears the
Ethernet signal.
[0018] The technical solution consistent with some embodiments is
hereinafter described in detail by reference to accompanying
drawings and preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is an exemplary flowchart of a method for
transmitting Ethernet signals in an OTN consistent with some
embodiments of the present disclosure;
[0020] FIG. 2 shows an example of how an OPU3-5v is divided into
timeslots consistent with some embodiments illustrated in FIG.
1;
[0021] FIG. 3 shows an exemplary structure of an apparatus for
transmitting Ethernet signals in an OTN consistent with some
embodiments of the present disclosure;
[0022] FIG. 4 shows an exemplary structure of an apparatus for
transmitting Ethernet signals in an OTN consistent with some
embodiments of the present disclosure; and
[0023] FIG. 5 shows an exemplary structure of a system for
transmitting Ethernet signals in an OTN consistent with some
embodiments of the present disclosure.
DETAILED DESCRIPTION
[0024] In the disclosed embodiments, an Ethernet signal such as
100GE signal is mapped to an adaptation protocol frame such as
Generic Framing Procedure (GFP) frame, Link Access Procedure for
SDH (LAPS) protocol frame, or High level Data Link Control (HDLC)
protocol frame. Afterward, the adaptation protocol frame is mapped
to a timeslot unit of a VCG composed of more than two OPUk's (k=1,
2, 3), respectively. Finally, the OPUk in the VCG with the mapped
adaptation protocol frame is mapped to the OTUk (k=1, 2, 3) of the
same rate. That is, if k=1, OPU1 is mapped to OTU1; if k=2, OPU2 is
mapped to OTU2; if k=3, OPU3 is mapped to OTU3. Moreover, before
the adaptation protocol frame is mapped to the timeslot unit, the
VCG is divided into timeslot units adaptable to Ethernet signals.
After the adaptation protocol frame is mapped to the timeslot
units, the OPUk in the VCG bears the Ethernet signals carried in
the adaptation protocol frame. After OPUk is mapped to OTUk, the
signals are transmitted in the OTN through OTUk. Therefore, the
Ethernet signals may be transmitted in the OTN transparently, thus
reducing the wavelength occupation and improving the bandwidth
utilization ratio.
[0025] Reference will now be made in detail to disclosed
embodiments illustrated in the accompanying drawings.
[0026] FIG. 1 is an exemplary flowchart of a method for
transmitting Ethernet signals in an OTN implementing embodiments
consistent with some embodiments. Taking the transmission of 100GE
signals in the OTN as an example, the detailed process may be as
follows:
[0027] Step 101: Two channels of 100GE signals are mapped to
adaptation protocol frames, respectively. The adaptation frame may
be a GFP, LAPS, or HDLC protocol; or four channels of 100GE signals
are mapped to adaptation protocol frames, which will not be
detailed here any further. In this embodiment, the adaptation
protocol may be GFP and the implementation may include at least the
following two steps:
[0028] Step 1011: Two channels of 100GE signals undergo Physical
Coding Sublayer (PCS) decoding. After the Inter-Packet Gap (IPG)
information and preamble information are removed, two channels of
MAC frames are extracted out.
[0029] Step 1012: The obtained two channels of MAC frame signals
are encapsulated into two channels of GFP-Framing (GFP-F) signals
respectively, or the MAC frame signals may be encapsulated into
GFP-Transparent (GFP-T) frame signals as required, which will not
be detailed any further.
[0030] Furthermore, connection sequence check bytes may be added in
the reserved overhead bytes of the two channels of GFP-F frames
respectively to check correctness of multiple channels of GFP
frames mapped to the OPU3-5v timeslot units.
[0031] During implementation of step 101, the VCG is divided into
timeslots. Five OPUs with a level-3 rate (namely, OPU3) constitute
a VCG, namely, OPU3-5v. The OPU3-5v is divided into two timeslot
units TS1 and TS2, which correspond to 100GE signals respectively.
FIG. 2 shows the division of an OPU3-5v composed of five OPU3's
(namely, OPU3-1, OPU3-2, OPU3-3, OPU3-4, and OPU3-5). As shown in
FIG. 2, the VCG (which is named "XJL") of the OPU3-5v is divided
and the OPU3's are assigned into multiple timeslot units: OPU3-1
and OPU3-3 are assigned to the timeslot unit "TS1" corresponding to
the first channel of 100GE signals; OPU3-2 and OPU3-4 are assigned
to TS2 corresponding to the second channel of 100GE signals; and
OPU3-5 adapts to the two channels of 100GE signals alternately,
namely, OPU3-5 is assigned to TS1 and TS2 alternately. The rate of
one OPU3 may be approximately 40 Gbps, the total rate of an OPU3-5v
is 200.752595 Gbps.+-.20 ppm, and the capacity of the payload area
of TS1 and TS2 is 100.3762975 Gbps.+-.20 ppm, which is greater than
100GE. Therefore, the MAC frames of the 100GE signals are fully
bearable, and the MAC frames may be transmitted transparently.
Moreover, when the link capacity may be adjusted through a Link
Capacity Adjustment Scheme (LCAS), and the bandwidth of the two
channels of 100GE signals may be adjusted by adjusting the quantity
of OPU3's.
[0032] It should be noted that the division mode is not restricted.
Other division modes may also applicable. For example, a VCG
(OPU3-6v) composed of six OPU3's is divided into three timeslot
units that adapt to 100GE signals respectively so that three
channels of 100GE signals can be mapped to OTUs, which will not be
detailed here any further. Moreover, the division of the VCG into
timeslot units is not necessarily simultaneous to step 101, and may
be performed anytime before the adaptation protocol frame is mapped
to the timeslot unit, which will not be detailed here any
further.
[0033] Step 102: The adaptation protocol frame may be mapped to the
timeslot unit. The corresponding implementation mode may include a
management frame is inserted into a GFP frame to implement
management and maintenance for the GFP frame. Alternatively, when
two channels of GFP frames are mapped and filled into TS1 and TS2
respectively, a certain number of idle frames may be inserted into
the two channels of GFP frames, respectively, so that the rates of
the two channels of GFP frames are equal to the rates of TS1 and
TS2, respectively. In this way, the TS1 and TS2 in the OPU3-5v
fully bear the MAC frames of the 100GE signals, respectively.
[0034] After the GFP frames are mapped to the OPU3, the quantity of
the OPU3's in a VCG may be adjusted through an LCAS to control the
link capacity. The specific implementation may include the
following.
[0035] An LCAS may be configured through a Network Management
System (NMS) so that the link capacity is adjusted to meet the
customer requirements, for example, an OPU3-5v composed of five
channel payload units.
[0036] Alternatively, according to the detected MAC frame traffic,
the LCAS adjusts the link capacity between 1*OPU3 and 5*OPU3 in
real time, and the bandwidth for transmitting the 100GE signals is
adjusted by adjusting the quantity of OPUs in the VCG.
[0037] Step 103: The OPU3 is mapped into OTU3 and output to the
OTN.
[0038] The five OPU3s in the OPU3-5v are assigned to five channels,
and encapsulated into an Optical channel Data Unit (ODU) whose rate
level is 3, namely, ODU3. Afterward, the ODU3 is encapsulated to
form an OTU3, modulated to the optical media, and output to the
OTN. The mapping between OPU3, ODU3 and OTU3 is described in the
ITU-T G.709 recommendations. In the foregoing embodiments, after
the 100GE signals are transmitted through the OTN to the receiving
end, the method for transmitting Ethernet signals in the OTN
consistent with some embodiments may further include: receiving the
OTU sent from the OTN, and demapping the OTU into an OPU;
corresponding to the process in FIG. 1, demapping the five channels
of OTU3's of the MAC frame that bears two channels of 100GE signals
into ODU3, and demapping the ODU3 into OPU3; demapping the VCG
composed of OPUs to adaptation protocol frames; corresponding to
the process in FIG. 1, demapping the OPU3-5v composed of five
channels of OPU3's into two channels of GFP frames, or demapping it
into LAPS frames or HDLC frames; demapping the adaptation protocol
frames into Ethernet signals; corresponding to the process in FIG.
1, recovering the MAC frame signal from the GFP frame (if a
connection sequence check byte is added into the GFP frame, the
recovery process further includes connection sequence check); and
afterward, inserting IPG information and preamble information into
the MAC frame for PCS coding, and then generating Ethernet signals
and output the signals to the Ethernet.
[0039] An apparatus for transmitting Ethernet signals in an OTN
consistent with some embodiments may include: a first adaptation
protocol frame mapping module, adapted to map an Ethernet signal to
an adaptation protocol frame; a first virtual concatenation module,
adapted to: divide a VCG composed of multiple OPUs into timeslot
units, and map the adaptation protocol frame to the timeslot units;
and a first line terminal module, adapted to: map the OPU into an
OTU so that the OTU bears the Ethernet signal, and output the OTU
to the OTN, thus implementing transmission of an Ethernet signal in
the OTN.
[0040] In order to resend the Ethernet signal carried on the OTU
transmitted in the OTN to the Ethernet, an apparatus for recovering
the Ethernet signal from the OTU may apply. This apparatus may
include: a second line terminal module, adapted to demap the OTU
sent by the OTN into an OPU; a second virtual concatenation module,
adapted to assemble the OPUs that derive from demapping performed
by the second line terminal module into a VCG, and demap the VCG
into an adaptation protocol frame; and a second adaptation protocol
frame mapping module, adapted to demap the adaptation protocol
frame that derives from demapping performed by the second virtual
concatenation module into an Ethernet signal, and output the
Ethernet signal to the Ethernet so that the Ethernet signal is
recovered from the OTU which bears the Ethernet signal.
[0041] FIG. 3 shows an exemplary structure of an apparatus for
transmitting Ethernet signals in an OTN consistent with some
embodiments. This apparatus includes: a first adaptation protocol
frame mapping module Z11, a second adaptation protocol frame
mapping module Z12, a first virtual concatenation module Z21, a
second virtual concatenation module Z22, a first line terminal
module Z31, and a second line terminal module Z32. In this
embodiment, Z11 and Z12, Z21 and Z22, and Z31 and Z32 may be
encapsulated together, respectively.
[0042] In the transmitting direction, the first adaptation protocol
frame mapping module Z11 is adapted to map the Ethernet signal into
an adaptation protocol frame, for example, map two channels of
100GE signals into an adaptation protocol frame such as GFP frame,
LAPS frame or HDLC frame. The first adaptation protocol frame
mapping module Z11 performs PCS decoding for the Ethernet signal
sent by the Ethernet, extracts the MAC frame from the decoded
signal, encapsulates the MAC frame into an adaptation protocol
frame, and sends the adaptation protocol frame to the first virtual
concatenation module Z21.
[0043] The first virtual concatenation module Z21 is adapted to
divide a VCG composed of multiple OPUs into timeslot units, for
example, divide a VCG composed of five OPUs into two timeslot
units, and map the adaptation protocol frame to the timeslot
units.
[0044] Further, the first virtual concatenation module Z21 may also
be connected with a management and control module Z4. As shown in
FIG. 4, the management and control module Z4 generates a capacity
control command according to the manually configured capacity
parameters, and sends the command to the first virtual
concatenation module Z21. The first virtual concatenation module
Z21 adjusts the capacity of the link connected with the first line
terminal module Z31 according to the capacity control command.
[0045] The first adaptation protocol frame mapping module Z11 may
also detect the MAC frame traffic, and send the MAC frame traffic
to the management and control module Z4. In this case, the
management and control module Z4 calculates the optimum link
capacity according to the traffic data sent by the first adaptation
protocol frame mapping module Z11, generates a capacity control
command, and sends the command to the first virtual concatenation
module Z21. The first virtual concatenation module Z21 adjusts the
capacity of the link connected with the first line terminal module
Z31 according to the capacity control command.
[0046] The first line terminal module Z31 is adapted to map OPU3
into OTU3 after receiving the OPU3 sent by the first virtual
concatenation module Z21, and output the OTU3 to the OTN.
[0047] In the receiving direction, the second line terminal module
Z32 is adapted to receive the OTU3 from the OTN, and demap the OTU3
into OPU3. The second virtual concatenation module Z22 is adapted
to receive the OPU3 from the second line terminal module Z32,
assemble the OPU3 into a VCG, and demap the VCG into an adaptation
protocol frame. The second adaptation protocol frame mapping module
Z12 is adapted to demap the adaptation protocol frame that derives
from demapping performed by the second virtual concatenation module
Z22 into a MAC frame, insert IPG information and preamble
information into the MAC frame, perform PCS encoding, generate an
Ethernet signal, and output the signal to the Ethernet.
[0048] The first adaptation protocol frame mapping module Z11 and
the second adaptation protocol frame mapping module Z12 may also be
set on both sides of the OTN. In a similar manner, the first
virtual concatenation module Z21 and the second virtual
concatenation module Z22, and the first line terminal module Z31
and the second line terminal module Z32 may also be set on both
sides of the OTN. As shown in FIG. 5, the first adaptation protocol
frame mapping module Z11, the first virtual adaptation module Z21,
and the first line terminal module Z31 are set on one side of the
OTN to convert an Ethernet signal to an OTU, and send the OTU to
the OTN. The second adaptation protocol frame mapping module Z12,
the second virtual adaptation module Z22, and the second line
terminal module Z32 are set on the other side of the OTN to recover
the Ethernet signal from the OTU that bears the Ethernet signal,
and may constitute a system where transmission of Ethernet signals
in the OTN may be implemented.
[0049] At the transmitting end of the OTN, the first adaptation
protocol frame mapping module Z11 is adapted to map an Ethernet
signal into an adaptation protocol frame. The first virtual
concatenation module Z21 is adapted to divide a VCG composed of
multiple OPUs into timeslot units, and map the adaptation protocol
frame to the timeslot units. The first line terminal module Z31 is
adapted to map the OPU into an OTU, and output the OTU to the
OTN.
[0050] At the receiving end of the OTN, the second line terminal
module Z32 is adapted to demap the OTU received from the OTN to an
OPU, where the OTU is output by the first line terminal module Z31
to the OTN. The second virtual concatenation module Z22 is adapted
to assemble the OPUs that derive from demapping performed by the
second line terminal module Z32 into a VCG, and demap the VCG into
an adaptation protocol frame. The second adaptation protocol frame
mapping module Z12 is adapted to demap the adaptation protocol
frame that derives from demapping performed by the second virtual
concatenation module Z22 into an Ethernet signal, and output the
signal to the Ethernet.
[0051] In some embodiments, an OPU3-5v is divided into two timeslot
units adaptable to the 100GE signals. After the two channels of
adaptation protocol frames of the MAC frames mapped to the 100GE
signals are mapped to the timeslot units, respectively, the five
OPU3's in the VCG bear the MAC frames of the two channels of 100GE
signals. Therefore, the 100GE signals may be transmitted in the OTN
transparently, with one channel of 100GE signals occupying only 2.5
chromatic wavelengths. Accordingly, wavelength usage may be
optimized, the bandwidth utilization ratio may be improved to
99.6%, and the cost of transmitting Ethernet signals on the OTN may
be reduced. Through the first adaptation protocol mapping module,
the first virtual concatenation module, the first line terminal
module, and the apparatus for transmitting Ethernet signals in an
OTN, the Ethernet signals may be converted to OTUs and sent to the
OTN, thus implementing transmission of Ethernet signals in the OTN.
Through the second adaptation protocol mapping module, the second
virtual concatenation module and the second line terminal module,
Ethernet signals are recovered from the OTUs that bear Ethernet
signals, and sent to the Ethernet for further transmission.
[0052] The method for transmitting Ethernet signals in an OTN
consistent with some embodiments may be implemented through
independent software stored in a computer-readable storage media.
For example, the software may be stored in a recording medium or a
disk medium pluggable into a computer system driver; stored in a
magnetic, optical or magneto-optical mode; or stored in a fixed
recording medium such as hard disk drive in a computer system, or a
solid-state computer memory. During execution of the software, the
Ethernet signals or OTU signals may be input into the computer
system. By invoking and running the software, the computer system
outputs and sends the OTU signals to the OTN for transmission, or
outputs and sends Ethernet signals to the Ethernet for
transmission.
[0053] The embodiments described above are only exemplary
embodiments that are not intended to limit the protection scope of
the present invention. It is apparent that those skilled in the art
can make various modifications and variations to the invention
without departing from the spirit and scope of the invention. The
invention is intended to cover the modifications and variations
provided that they fall in the scope of protection defined by the
following claims or their equivalents.
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